An autonomous traveling apparatus (also referred to as an automatic traveling apparatus) that determines its own operation by using sensor information and acts autonomously has been developed. For example, an optical distance measuring device (distance measuring sensor) is able to measure a distance to an object present in a measurement range and obtain a one-dimensional or two-dimensional distance data map, and is thus used as a safety device which is used for the autonomous traveling apparatus to detect and avoid an obstacle.
As to a configuration for detecting an obstacle by a moving body like the autonomous traveling apparatus, for example, Japanese Laid-Open Patent Publication No. 2013-254474 discloses an obstacle detecting apparatus including a depth sensor, a depression angle estimating portion which estimates a depression angle of the depth sensor based on a distance image obtained from the depth sensor, and a detecting portion which detects an obstacle present on a road surface based on the depression angle, a height of the depth sensor, and a distance of the distance image. Even when the depression angle varies due to shaking of the depth sensor during traveling of a moving body, the obstacle detecting apparatus is able to detect the obstacle on the road surface on which the moving body travels.
Moreover, Japanese Laid-Open Patent Publication No. 2015-106254 discloses an autonomous moving body aiming to accurately detect a level difference even in a state where the autonomous moving body is inclined. This autonomous moving body includes a driving unit, a plurality of distance measuring units installed so as to face a road surface and configured to measure a distance to the road surface, a control unit configured to compare the distance measured by the distance measuring units with a threshold and to control the driving unit, an inclination angle detecting unit configured to detect an inclination angle of a main body of the moving body, and a correction unit configured to correct at least one of the distance measured by each distance measuring unit and the threshold depending on the inclination angle of the main body of the moving body detected by the inclination angle detecting unit.
With a configuration in which an obstacle is detected by using a distance measuring device, it is possible to measure a distance to an object by the distance measuring device, but when a ground is included in a measurement range (measurement space region) by the distance measuring device, it is difficult to detect the ground and an obstacle to be detected while distinguishing them.
Even when setting is performed so that the measurement space region does not include the ground in order to solve such a problem, the ground appears in the measurement space region when a vehicle body and the distance measuring device shake or at a position where concave and convex on the ground exist or inclination of the ground changes, resulting that it is difficult to detect the ground and the obstacle to be detected while distinguishing them. Such a moving body including an obstacle determining apparatus detects the ground as an obstacle even when there is no object to be an obstacle for traveling and needs to perform control to stop or slow down for safety, so that usability is lowered.
Moreover, in order to detect the ground and the obstacle while distinguishing them when setting is performed so that the measurement space region includes the ground, it is necessary to discriminate whether a measurement point is the ground, for example, based on a relative angle between the distance measuring device and the ground and a measured distance. However, even with such a method, the relative angle between the distance measuring device and the ground varies when the vehicle body and the distance measuring device shake or at a position where inclination of the ground changes, so that it is difficult to perform accurate discrimination.
As a configuration for detecting the ground and the obstacle while distinguishing them, it is considered to apply data processing to output data of the distance measuring device and correctly recognize the ground as an object different from the obstacle. In this case, however, load of the data processing increases. Further, when shaking due to an impact or a change in the inclination of the ground is corrected by the data processing, algorithm becomes more complicated and the load of the data processing further increases. Thus, a high-performance and high-cost processing system is required to perform the data processing with a large load.
With a technique described in Japanese Laid-Open Patent Publication No. 2013-254474, in order to detect the obstacle on the road surface even when the depression angle at which the depth sensor shakes varies while the moving body travels, the relative angle between the ground and the sensor is estimated by data processing, whereas considerable arithmetic processing needs to be performed based on complicated algorithm for the estimation and a high-performance processing device is needed.
A technique described in Japanese Laid-Open Patent Publication No. 2015-106254 is a technique by which the distance to the road surface is measured to detect concave and convex on the ground by the distance measuring unit, but an obstacle such as another moving body that is in front of the moving body is difficult to be detected.